In order to obtain a transistor having a high emitter current density and a high-frequency transistor, it is well known that the ratio of the emitter region spreading area to the emitter region area should be made as great as possible.
As such a transistor, there is one in which the emitter region is constructed in the form of a net and a base region makes inroads into the meshes of the net of the emitter region as disclosed in Japanese Pat. No. 24384/1969.
In such a construction, the ratio of the emitter region spreading area to the emitter region area certainly increases, and hence, a larger amount of current than in the prior art flows from the emitter region to the base region. In this case, however, the concentration of current often arises in the interval in which the current flows from an emitter electrode to a base electrode. For this reason, a transistor of high emitter current density and a high-frequency transistor which are satisfactory cannot be produced by merely increasing the ratio of the emitter region spreading area to the emitter region area. The inventor has taken note of this fact, and has made the present invention.